Question

what is the molarity of each ion in a solution prepared by dissolving 0.53g of Na2SO4, 1.196g of Na3PO4, and 0.222g of Li2SO4 in water and diluting to a volume of 100.mL

Answer 1

Na2SO4= 0.04mol/L

Na3PO4=0.07mol/L

Li2SO4=0.02mol/L

Mol/L= M or Molarity

Step-by-step explanation:

Step 1

Find the molar mass for each compound (molar mass unit is g/mol and is equal to the mass number present on the element)

Na2SO4 = 142g/mol

Na2= (23*2)=46g/mol

S=32g/mol

O3=(16*4)=64g/mol

Hence, 46+32+64=142 g/mol

Na3PO4= 164g/mol

Li2SO4=110g/mol

Step 2

Using the molar mass determine the mols of each compound. (mol=g/molar mass)

Na2SO4 = 0.004mol

0.53g/142gmol

=0.00373mol

=0.004mol

Na3PO4= 0.007

Li2SO4=0.002

Step 3

Calculate the Molarity (mol/L)

Na2SO4= 0.04mol/L

100mL/1000= 0.1L

NB Molarity is always in the units mol/L hence we must convert mL into L

0.004/0.1

=0.04mol/L

Na3PO4= 0.07mol/L

Li2SO4=0.02mol/L